Using the Sun as a Telescope

Very cool idea. I had heard of this before, but never heard any details. We need to put something out at 550 AU from earth, which is where the focus begins. From there, we could see far better than any other telescope could see. [Link]

Interestingly enough, some of the earliest work on solar sails in interstellar environments came out of the attraction of taking advantage of the Sun’s own gravitational lens. Push some 550 AU out and you reach the point where solar gravity focuses the light of objects on the other side of the Sun as seen from a spacecraft. Note two things: At 550 AU, electromagnetic radiation from the occulted object is boosted by a factor of roughly 10⁸. Secondly, gravity-focused radiation does not behave like light in a conventional optical lens in one important sense. The light does not diverge after the focus as the spacecraft continues to move away from the Sun. Indeed, the focal line extends to infinity.

The Italian aerospace company Alenia Spazio (based in Turin) began investigations into inflatable sail technologies as long ago as the 1980s. Since then, physicist Claudio Maccone has continued to investigate a mission he calls FOCAL, a probe to the gravity focus. Maccone sees such a mission as inevitable, for it takes advantage of an asset every technological civilization will ultimately want to exploit. Here’s how he puts it in his 2002 book The Sun as a Gravitational Lens: Proposed Space Missions:

As each civilization becomes more knowledgeable they will recognize, as we now have recognized, that each civilization has been given a single great gift: a lens of such power that no reasonable technology could ever duplicate or surpass… This lens is the civilization’s star; in our case, our Sun. The gravity of each star acts to bend space, and thus the paths of any wave or particle, in the end creating an image just as familiar lenses do….Every civilization will discover this eventually, and surely will make the exploitation of such a lens a very high priority enterprise.

It's great, but it's almost a fixed in place telescope. Whatever you want to look at had better be very close together in the sky.